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ST Ericsson already showcased NovaThor L8580 Cortex A9 processor @ 2.8 GHz at CES 2013. The processor features a technology called eQuad, and as I previously noticed there’s no mention of the number of cores at all on the website and many websites reported the processor featured 4 cores. The processor actually features 2 Cortex A9 core, but thanks to FD-SOI technology they are able to do the equivalent of a Quad Core big.LITTLE processor (i.e. 2x Cortex A15 + 2x Cortex A7) electrically.

Since this is just done electrically, you can use the same software as before and will consume much less power, whereas big.LITTLE requires a lot of kernel work. A Cortex A9 will obviously be less powerful than a Cortex A15, but since they are able to boost the frequency up to 3GHz (probably limited to 2.5Ghz in actual product) this can compensate the lower performance, and the die size will be much smaller than on a quad core big.LITTLE processor, since you only need 2 cores for similar power consumption and performance. Charbax uploaded a video with a nice explanation of the system at MWC2013. The first part of the video is very interesting as it explains the technology and its advantage. One particularly interesting part is when Charbax asked about big.LITTLE, and ST Ericsson representative explains that big.LITTLE processing is not so interesting now that FD-SOI is available, and it will also end up in cortex A15 processor. He did not say FD-SOI eQuad was a big.LITTLE killer, but it was close :). He may be right about IKS big.LITTLE implementation, but with HMP big.LITTLE, where they can use all cores, big.LITTLE will certainly retain its advantage. What do you think?

Update: If you want to know more about eQuad, you can read FD-SOI eQuad White-Paper (15-page PDF), that explains the technology, and also explains that heterogeneous multiprocessing (HMP) is a promising technology, but it’s highly complex both in terms of hardware and software, and it may take a few years to reach its full potential.

We’ve first heard about ST Ericsson NovaThor L8580 in July 2012, and the company demonstrated their new processor at CES 2013. This SoC features 4 (or is it 2?) Cortex A9 cores, and a PowerVR SGX544 GPU, but the real advantage of this processor is the new process technology called FD-SOI (Fully Depleted Silicon On Insulator) which, combined with some other power and performance optimization techniques, allows some fun stuffs such as:

2.8 GHz dual core operation

1 GHz operation at 0.63V instead of 1.1V when using bulk CMOS technology.

You can see those 2 use cases in the video demo. In the first demo, a phone prototype based on L8580 @ 2.8Ghz is clearly faster than the Samsung Galaxy S3 based on Exynos 4412, and the second demo shows power measurement of the prototype when ran at 1GHz.

Other key features of L8580:

Low-power eQuad processor clocked at up to 2.5Ghz based on ARM Cortex-A9 processor

ST Ericsson is working on a new application processor manufactured with 28 nm FD-SOI technology by ST Microelectronics. The new processor NovaThor L8580 features 2 Cortex A9 core that can be clocked at 2.3 GHz and is aimed at smartphones and tablets.

The company also improved power efficiency, as L8580 consumes 35% less energy than L8540 (28 nm) when clocked at 1.85 GHz (maximum frequency for L8540). If you need even lower power consumption, L8580 can be clocked at 1.0 GHz with an input voltage of 0.6 V, whereas current competitors’ processors require at least 0.9V to operate at 1GHz.

ST-Ericsson estimates that Novathor L8580 will be able to offer an extra day battery life compared to L8540 on a typical smartphone, which correspond to about 4h and 2h30 extra for web browsing and HD video playback respectively.

NovaThor L8580 SoC will embed a PowerVR SGX544 GPU clocked at 600 MHz, a DDR2 controller and an LTE modem..

CPU hotplug is used on ARM platform as a power management feature for aggressive low power use cases. It has not been initially designed for that purpose, which implies some constraints on its use but the same power consumption level can’t be reached with the scheduler load balance and/or additional features like cpuset up to now. This presentation will discuss how CPU hotplug matches the low power use case requirements and how we can get closer to this behavior with sched_mc. Then we will also show what prevents the scheduler to reach the same power consumption level as CPU hotplug and how we can solve some of these issues. This presentation is aimed at anybody who is interested to understand why ARM platforms still use CPU hotplug and what should be done to replace CPU hotplug by a load balance decision.

The two phones are the HTC Sensation (Z710t) and Via Mobile Smartphone (I could not find any names) targeted at the Chinese market, although they plan to sell them in Europe and US later. The Via Mobile phone features a 4.3″ capacitive touchscreen, HSPA+ (14.4Mbps) and a 5MP rear camera. The smartphones were apparently running gingerbread, but they will also release an Android ICS version soon, as the latest Android release is already running on their hardware reference platform.

Andrea Gallo, Chief Linux Architect in the Smartphone and Tablet Solution organization in ST-Ericsson and part of the Linaro Technical Steering Committee, explains how a common Linux ARM kernel benefits ST Ericsson Snowball development platform.

Abstract:
Last March, the ARM Linux community got shaken by the complaints by Linus Torvalds for its lack of proper structure and organization. This is totally true and mainly due to the large number of different SoC vendors, each one integrating the ARM IP’s in a slightly different variant. Linaro immediately accepted the challenge to drive the kernel alignment of the ARM community and most ARM Linux experts got together and agreed on the way forward as early as May 2011 at the Developers’ summit in Budapest. ST-Ericsson is a founding member of Linaro and some key ST-Ericsson engineers are assigned to Linaro and specifically to this kernel alignment working force. In the speech, Andrea describes how ST-Ericsson is contributing to this important task and which improvements and benefits are measured when ported onto the Snowball low cost development kit, based on ST-Ericsson Nova A9500 Application Processor.

ARM unveiled the Cortex A7, a new core with higher performance than the Cortex A8 (1.5x) and with 5 times less power consumption. It will be used in conjunction with Cortex-A15 Core and allows big.LITTLE processing where the Cortex A7 (companion core) takes care of the low performance, low power tasks (social network, email, SMS, phone calls) and the Cortex A15 kicks in for high performance tasks such as video processing and gaming.

ARM today announced the ARM® Cortex™-A7 MPCore™ processor – the most energy-efficient application class processor ARM has ever developed, and big.LITTLE processing – a flexible approach that redefines the traditional power and performance relationship. The Cortex-A7 processor builds on the low-power leadership established by the Cortex-A8 processor that is at the heart of many of today’s most popular smartphones. A single Cortex-A7 processor delivers 5x the energy-efficiency and is one fifth the size of the Cortex-A8 processor, while providing significantly greater performance. The Cortex-A7 processor will enable a rich user experience in sub-$100 entry level smartphones and help connect the next billion people in developing markets.

Big.LITTLE processing, enabled by Cortex-A7, achieves this by pairing the best of the high-performance Cortex-A15 MPCore and ultra-efficient Cortex-A7 processors. Big.LITTLE processing allows devices to seamlessly select the right processor for the right task, based on performance requirements. Importantly, this dynamic selection is transparent to the application software or middleware running on the processors

ARM says Cortex A7 processor is fully compatible with other Cortex-A series processor and incorporates all of the features of the high-performance Cortex-A15 processor including virtualization, large Physical Address Extensions (LPAE) NEON advanced SIMD, and AMBA 4 ACE coherency.

A single Kingfisher processor can deliver 5x energy-efficiency, 50% greater performance and is one fifth the size of the ARM Cortex-A8 processor, which powers many of today’s most popular smartphones.

Cortex A7 / A8 Power & Performance Comparison

The Cortex A7 can be used:

As a Standalone CPU (with up to 4 cores) as it offers more performance than 2011 mainstream smartphone CPU as it provides up to 20% more performance while consuming 60% less power,

big.LITTLE processing addresses one of today’s industry challenges: how to create a System on Chip (SoC) that provides both high performance as well as extreme power efficiency to extend battery life. big.LITTLE connects the performance of the ARM Cortex-A15 MPCore™ processor with the energy efficiency of the Cortex-A7 processor, and enables the same application software to be seamlessly switched between them. By selecting to optimum processor for each task big.LITTLE can extend battery life by up to 70%.

Since Cortex A7 and Cortex A15 use the same instruction set (ARMv7a), software developers won’t have to care on which core their software will run to take advantage of lower power consumption and longer battery life, although it will still possible to switch between cores with a software switcher.

ARM has done a big.LITTLE processing demo using Android Browser in Gingerbread using a big.LITTLE aware Power Management Driver. They will provide open source firmware for “state migration” between Cortex A7 and Cortex A15, but I could not find further info on this yet.

There is an obvious advantage in mobile devices like smartphone and tablets, but ARM expects this technology to also be used in datacenters where they have pressure to keep electricity bills low. The Cortex A7 would be active during periods of low traffic (e.g. night time, week-end) and during burst of traffic the Cortex A15 would take care of the extra load.

Cortex A15 will have a bit over than twice the performance of the Cortex A7, but the Cortex A7 will consume 3.5 times less than the Cortex A15.